This invention generally relates to fibrous webs and fibrous web laminates suitable for use in articles used to absorb, distribute and retain body liquids, such as disposable diapers, sanitary napkins, incontinence garments, and the like, and to a method and apparatus for making the same.
Nonwoven materials, such as spunbonded webs and carded webs, have been used as bodyside liners in disposable absorbent articles. Typically, very open, porous liner structures have been employed to allow liquid to pass through them rapidly, thereby keeping the wearer's skin separate from the wetted absorbent core underneath the liner. Also, other layers of material, such as those constructed with thick, lofty fabric structures, have been interposed between the liner and absorbent pad for the purposes of handling surges of liquids and reducing flow back of liquids.
Previous methods and apparatus for aperturing nonwoven webs, which have been used as bodyside liners in disposable absorbent articles, have created openings in the nonwoven webs which are larger than the spaces between the fibers in the nonwoven webs. The prior methods and apparatus have often included the use of rotating rolls having projections extending therefrom. The projections are often heated and are used to pierce the webs to form apertures within the webs. The heated projections have been used to create fused perimeters around the resultant apertures. The apertured bodyside liners of the prior art purportedly improve fluid intake rates and improve the handling of low-viscosity fecal material. The previous methods and apparatus have generally been designed to aperture relatively thin webs.
However, aperturing lofty or thick nonwoven webs may be desirable for various reasons, such as, for example, to create three-dimensional topography and/or to improve the aesthetics of the nonwoven materials. Previous methods and apparatus are less effective when aperturing lofty or thick nonwovens because the apertures tend to close once the projections are removed from the lofty web. Additionally, tension in the lofty nonwoven web also tends to close the apertures made by traditional methods and apparatus. Finally, previous methods and apparatus tend to compress the entire fibrous nonwoven web.
Therefore there is a need for a method and apparatus to create lofty nonwoven webs containing apertures that are well defined and remain well defined after processing and handling. There is also a need for a method and apparatus to create lofty nonwoven webs having apertures wherein the non-apertured portions remain lofty thereby creating three-dimensional topography in the lofty nonwoven web.